Qubit™ 3 Fluorometer - FAQs

View additional product information for Qubit™ 3 Fluorometer - FAQs (Q33216)

13 product FAQs found

How does the accuracy and sensitivity of the Qubit quantitation assays using the Qubit fluorometer compare to a microplate reader?

The accuracy and sensitivity of the Qubit quantitation assays are the same as that of a microplate reader. This was a requirement during product development. The detection limits for each Qubit kit can be found on the corresponding product manual, which can be found by searching our website by keyword or catalog number.

Find additional tips, troubleshooting help, and resources within our Nucleic Acid Quantification Support Center.

Can the Qubit kits give an indication of sample quality in nucleic acid samples?

No. The Qubit DNA and RNA kits only quantify the amount of either DNA or RNA in the sample. The Qubit fluorometer cannot take absorbance readings to provide a A260/A280 ratio or detect protein in nucleic acid samples. This can be done with the NanoDrop instrument. If your sample contains protein or other contaminants that can affect the assay, it should be further purified.

If your sample may contain both DNA and RNA, one may use either (or both) the DNA and RNA Qubit kits and compare with samples treated with either RNase or DNase to get an accurate determination of DNA or RNA, respectively.

Can I use the Quant-iT and Qubit Kits with other fluorometers?

All Quant-iT and Qubit kits are compatible with all fluorometers and microplate readers that have the appropriate light sources and filters. You won't have access to the algorithm in the Qubit fluorometer for generating the standard curve provided by the instrument, instead, you must make a few dilutions of the highest standard DNA or RNA (Standard #2) in the Qubit kits to generate a standard curve with multiple data points.

Can I use other kits besides the Ion Library Equalizer Kit for library normalization?

If you are not using the Ion Library Equalizer Kit for library normalization, one of the following can be used (but the library should be at 100 pM):

- Ion Library TaqMan Quantitation Kit
- Qubit 3.0 Fluorometer or Qubit 2.0 Fluorometer
- Qubit dsDNA HS Assay Kit
- Agilent 2100 Bioanalyzer Instrument
- Agilent High Sensitivity DNA Kit

Find additional tips, troubleshooting help, and resources within our Next-Generation Sequencing Support Center.

With the Oncomine BRCA Research Assay, which method do you recommend for quantifying gDNA?

We recommend two methods for gDNA quantification:

- Qubit 3.0 Fluorometer (Cat. No. Q33216) with Qubit dsDNA HS Assay Kit (Cat. Nos. Q32851, Q32854)
- qPCR using TaqMan RNase P Detection Reagents Kit (Cat. No. 4316831)

I'm getting a low reading with my Invitrogen Qubit fluorometer. What could be causing this?

- The sample is out of range. Use a sample that is more concentrated or use a lower dilution (for example, 20 µL in 180 µL instead of 10 µL in 190 µL).
- View the Fluorescence vs. Concentration graph in the Results screen to confirm that the values for the samples fall between the values of the standards (see the manual).
- Ensure that you have prepared the Invitrogen Qubit working solution correctly (1:200 dilution using the buffer provided in the kit).
- Ensure that you have prepared the standard tubes correctly (10 µL of each standard in 190 µL of Qubit working solution).
- Ensure that the standard and sample tubes are filled to 200 µL.
- Protect the Invitrogen Qubit reagent and working solutions from light.
- Select the correct Invitrogen Qubit Fluorometer assay for the assay you are performing and calibrate the fluorometer correctly. Standards must be used in the correct order.
- Ensure that the assay is performed entirely at room temperature.

I'm getting a high reading with my Invitrogen Qubit fluorometer. What could be causing this?

- The sample is out of range. Use a sample that is less concentrated.
- View the Fluorescence vs. Concentration graph in the Results screen to confirm that the values for the samples fall between the values of the standards (see the manual).
- Ensure that the lid is closed while reading standards and samples.
- Prepare samples and standards according to the instructions in the Qubit assay kit you are using.
- Ensure that the assay is performed entirely at room temperature.

What kind of tubes do I need to buy for the Invitrogen Qubit Fluorometer?

For Qubit 4 and older instruments, use thin-walled, clear 0.5 mL PCR tubes such as Invitrogen Qubit Assay Tubes (http://www.thermofisher.com/order/catalog/product/Q32856). For Qubit Flex Fluorometers, use thin-walled 200 µL polypropylene tubes such as Invitrogen Qubit Flex Assay Tube Strips (http://www.thermofisher.com/order/catalog/product/Q33252). Other types of tubes can have auto-fluorescence or a frosted area for writing and may interfere with the assay.

Do I have to use new standards every time when using the Invitrogen Qubit Fluorometer?

No. But we do recommend using new standards every time you make a new working solution, so that the working solution used in your standards is the same as that used in your samples.

I already have the original Invitrogen Qubit 1.0 Fluorometer. Is the Invitrogen Qubit 4.0 Fluorometer any different?

The Qubit 4.0 Fluorometer employs a large, robust color touch screen for seamless workflow navigation and exports data to a USB drive or directly to your computer via a USB cable for efficient data management. Also, the instrument has a built-in Reagent Calculator and can be personalized to show only the frequently used assays, to add new assays, including user-defined assays created with the MyQubit assay design tool, and to display in the language of your choice including English, French, Spanish, Italian, German, simplified Chinese, and Japanese.

Can the Invitrogen Qubit Fluorometer give an indication of sample quality?

No. The Qubit fluorometer cannot take absorbance readings to provide a A260/A280 ratio or detect protein in nucleic acid samples. This can be done with the NanoDrop instrument. If your sample contains protein or other contaminants that can affect the assay, it should be further purified.

The Qubit DNA and RNA kits only quantify the amount of either DNA or RNA in the sample. If your sample contains both DNA and RNA, one may use either (or both) the DNA and RNA Qubit kits and compare with samples treated with either RNase or DNase to get an accurate determination of DNA or RNA, respectively.

Why are my UV absorbance readings higher than the Invitrogen Qubit Fluorometer readings?

UV absorbance readings measure anything that absorbs at 260 nm, including DNA, RNA, protein, free nucleotides, aromatic amino acids and other bases. Quantification with the Qubit Fluorometer only measures the molecule you are interested in, resulting in a quantity that is almost always lower than the A260 reading.

I already have a NanoDrop instrument. Why should I use the Invitrogen Qubit Fluorometer?

The NanoDrop instrument uses UV absorbance, which cannot distinguish between DNA, RNA, free nucleotides, and other contaminants. The Qubit Fluorometer utilizes specifically designed fluorometric technology using Invitrogen dyes to quantitate biomolecules of interest. These fluorescent dyes emit signals only when bound to specific target molecules, even at low concentrations.